Skiving-machine.



F. W. CHRISTY. SKIVING MACHINE.

APPLICATION FILED AUG.7, l9l5.

' ig mgw Patented. Jan. 22,1918.

2 SHEETS-SHEET 1.

F. W. CHRISTY.

SKIVING MACHINE.

APPLICATION FILED Aue.. 1915.

LQM WQ, Patented 56111221918.

2 SHEETS-SHEET 2.

as Praia n.

FRANK W. CHRISTY, 015 BEVERLY, MASSACHUSETTS, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO UNITED SHOE MACHINERY CORPORATION, OF PATERSON, NEW JERSEY,

A CORPORATION OF NEW JERSEY.

' SKIVING-MACHINE.

Application filed August 7, 1915.

T0 aZZ whom it may concern:

Be it known that I, FRANK IV. CHnIs'rY, a citizen of the United States, residing at Beverly, in the county of Essex and State of Massachusetts, have invented certain new and useful Improvements inSkiving-Machines; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art towhich it appertains to make and use the same.

The present invention relates to skiving machines and'more particularly to mechanism for producing a true cutting edge upon the tubular skiving knife employed in machines of this type. 3

In order that the best results shall be obtained in skiving leather and analogous 'material it is essential that the path of travel of the cutting edge shall not vary, and to secure this condition when employing a tubular skiving knife the cutting edge must conform accurately to a circle which is concentric with the axis of rotation of the knife. The object of the present invention is to provide improved mechanism for forming a cutting edge upon a tubular skiving knife which is independent of eccentricities in the knife blade and conforms accurately to a true circle of rotation of the knife.

In machines of this type having a tubular skiving knife it is customary to employ a gage member which serves to determine the position of the work accurately with relation to thecutting edge of the knife, and a cooperating presser member which maintains the work in contact with the gage member to insure its proper location with respect to the knife. The cooperating gage and presser members are positioned adjacent opposite surfaces of the knife and in order to further insure that the position of the work shall be determined by the gage memher the bevel cutting face is formed entirely upon the surface adjacent to the gage member, thus placing the cutting edge at the opposite surface; With this construction and arrangement the tendency of the knife when operating on the-work is to constantly force the skiv'ed mater1al against thegage member and aid. the presser member in its operation, as will be obvious to those skilled in; theart.

Specification of Letters Patent.

is mounted upon one end of a rotary knife Patented Jan. 22, 191%.

Serial No. 44,297.

lVith the above object in view a feature of the invention contemplates the provision in a skiving machine having a tubular skiving knife provided with substantially concentric inner and outer surfaces and means for rotating the knife, of means for grinding a bevel face upon one surface to put the cutting edge at the opposite surface :of the knife, a grinding member engaging with the opposite surface of the knifeand means for determining the position of the two grinding members with respect to opposite surfaces of the knife. I a

A further feature of the invention contemplates the provision in a skiving machine comprising a tubular skiving knife provided with substantially concentric inner and outer surfaces and means for rotating the knife, of means for grinding a bevel face upon one surface to put the cutting edge at the opposite surface of the knife, a grinding member engaging with the opposite surface of the knife, and means for positively limiting the movement of the grinding member in one direction to gage the position of the grinding member with relation to the knife.

Still further features of the invention consist in certain novel features of construction, combinations and arrangements of parts hereinafter described and claimed, the advantages of which will be obvious to those skilled in the art from the following description.

In the accompanying drawings illustrating the preferred form of the invention; Figure 1 represents a longitudinal section in elevation of a skiving machine embodying the several features of the invention; Fig.

.tion is shown in connection with a skiving machine of the type disclosed in thepa-tent to Alexander No. 1,117,541, dated November 17, 1914. This machine is provided with a tubular skiving knife indicated at 1 which shaft 3 journaled in the casing l of the ma- L05 chine. The skiving knife comprisesa-knife blade 5 which is supported upon a knife carrier 6 and is clamped in an external knife holder 7 by clamping members 8 which are actuated by clamping bolts 9 in the usual manner. In this type of machine the position of the work is determined by a gage member (not shown) supported in an overhanging arm 10 which carries an adjustable head 11 to position the gage member over the knife and vary the location of the gage member relative to the knife in the usual manner. The knife aids in keeping the work in contact with the gage member by the provision of a bevel cutting face formed upon the outer surface of the knife, as shown clearly in Figs. 1 and 2. This bevel cutting face is produced by a grinding disk 15 which is journaled in a supporting bracket 16 actuated to move the grinding disk into and out of engagement with the knife by a member 18, and the grinding disk is rotated when in engagement with the knife edge by a drive pulley 19 operated in any suitable mannerand all as described in the patent above referred to.

In operating upon thin, pliable material to secure the best results it is essential that a keen cutting edge shall be employed which follows without the slightest deviation a predetermined path of movement. In skiving machines having a tubular skiving knife which is either solid or formed as a thin band clamped in a retaining holder, considerable difficulty is experienced, and more especially in the case of the band knives, in producing a circular cutting edge which is concentric throughout with the axis of rotation of the knife. In the present invention a second grinding member is arranged to engage with the opposite surface of the knife in a manner to cause the inequalities or eccentricities in the surface of the knife to be removed without weakening the cutting edge, or without beveling the opposite surface suiliciently to counteract the tendency of the bevel cutting face to press the work against the gage member. In the illustrated embodiment of the invention the internal grinding member and actuating mechanism comprises an attachment which is employed intermittently to true up the knife edge whenever desired, and which is removed during the operation of the machine. To this end a grinding diskQO is secured upon the end of a spindle 21 which is journaled in a depending bracket 23. The grinding disk bracket is connected to the head 11 through a dovetailed block 24 which is supported in the position normally occupied by the gage member. \Vhen the 'bracket 23 is supported by the head the grinding disk is positioned within the knife in the position shown in Fig. l with the spindle 21 s1upported-parallel to the knife shaft 3. In this position the periphery of the grinding disk engages withthe inner surface of the knife in a straight line path of contact and serves to remove the inequalities in the surface without producing'auy substantial bevel or concavity to weaken the cutting edge. The grinding disk may be readily adjusted with relation to the kmfe blade through the provision of an adjustable connection between the bracket 23 and block 24. The bracket 23 is provided with a slot 25 which receives a bolt 26 threadedly engaging with theblock 24; and retained in position by clamping washers 27; Upon loosening the bolt the bracket may be moved either vertically or angularly to locate the grinding disk in any desired position.

7 In order that the grinding member shall act most efficiently upon the surface of the knife to remove eccentricities in the surface and form a true cutting edge it is essential that the grinding member shall be. located in a fixed predetermined positionwith relation to the rotating knife. In the present invention this is conveniently accomplished by providing means for positively limiting the movement of the grinding member in one direction either toward or from the surface of the knife, and cooperating mechanism which constantly tends to maintain the grindingmember in the position determined by the limiting gage. It will be obvious to those skilled in the art that the preferred method of removing inequalities in the surface of the knife is to gradually grind away thepro ectmg portions of the surface until a true cylmdrical surface 1s obtained. In

the illustrated embodiment of the invention this is accomplished by providing gaging mechanism which limits the movement of the. grinding diskiin the directionof the inner surface of the knife and determines the operative position of the grinding disk with relation to the knife, and cooperating means for yieldingly maintaining the grinding disk in the position determined by the gage member. The bracket 23 is supported upon anadjustable head 11 slidingly supported in the overhanging arm 10 and provided with an elongated slot receiving a spring 28 which constantly tends to maintain the head in engagement with the end of an adjustable gaging screw 29. The opposite end of the spring 28 bears against a thrust block 31 which is secured in the arm 10 and is loosely received in the slot, as shownclearly in Figs. 1 and 2. With this construction the movement of the grinding disk toward the knife is determined by the position of the gaging screw '29 and the spring 28 causes a continual grinding action to be exerted upon the surface ofthe knife until this position isrea chedr V .In order to further improve the action of the grinding disk and insure that .theidisk shall maintain a straight linepath of con tact with the knife, mechanism is provided for imparting a bodily movement to the disk in a rectilinear path extending in the direction of the axis of the knife. In the illustrated embodiment of the invention the skiving knife is substantially cylindrical in form with concentric inner and outer surfaces, and the movement of the grinding disk is parallel to the axis of the knife. To this end the spindle 21 is journaled in a sleeve bearing 30 which is threadedly mounted in the bracket 23 and is conveniently ad justed through a knurled adjusting member 32, as shown clearly in Fig. 1. \Vith this construction an axial movement is conveniently imparted to the grinding disk during its operation by rotating the bearing 30 which is provided with a coarse thread to move the disk across the surface of the knife.

The friction of the bearings tending to retard the rotation of the grinding disk may be suflicient to cause a relative movement of the peripheral surface of the grinding disk and the inner contacting surface of the knife to exert a grinding action upon the knife. In addition, to insure that the grinding action shall be properly performed, driving mechanism is provided for rotating the disk in the direction of rotation of the knife to cause the peripheral surface of the disk to move at a lower rate of speed than the contacting surface of the knife. This is accomplished by providing a stub shaft 34: which has a reduced threaded end 35 received in a threaded recess located centrally in the knife supporting head 37. The shaft 34: is located axially with relation to the knife shaft by an enlarged head 36, one face of which engages with the face of the head 37 when the two cooperating drive pulleys 38 and 39 are alined with one another. The drive pulley 38 is mounted upon the shaft 34 and the pulley 39 is secured to the spindle 21 and is driven from the pulley 38 through a connecting belt 4.0 to rotate the spindle at substantially the same speed as the shaft. It will be obvious that as the bracket 23 is adjusted and the grinding disk is moved axially during its operation a movement of the pulleys 38 and 39 will take place relative to one another but as this movement is relatively small and as no substantial driving strains are transmitted by the belt 40, the belt will give sufiiciently to permit these movements without affecting the operation of the device. Vith the above construction it will be noted that the grinding attachment may be readily applied to the machine by supporting the bracket 23 in the adjustable head 11 and threading the stub shaft into the cooperating recess in the knife head, the various parts being so constructed and arranged with respect to one another that the grinding attachment may be immediately operated without the necessity for substantial adjustment.

lVhile'it is preferred to; employ the specific construction and arrangement of parts shown and described, it will be understood that this construction and arrangement is not essential except so far as specified in the claims, and may be changed or modified without departing from the broader features of the invention.

The invention having been described, what is claimed is 1. A skiving machine comprising a knife holder, a thin tubular knife blade, means for clamping the knife blade to the holder, a pair of grinding members positioned adjacent the inner and outer surfaces of the knife blade, and means for determining the position of the two grinding members with respect to opposite surfaces of the knife blade, constructed and arranged to cause the formation of a true circular cutting edge independently of eccentricities in the inner and outer surfaces of the knife blade.

2. A skiving machine, comprising a tubular skiving knife, a pair of grinding members supported adjacent to the inner and outer surfaces of the knife respectively, means for positioning one of the grinding members to form a beveled cutting face upon one surface of the knife, gaging mechanism for positively limiting the movement of the second grinding member in a direction toward the adjacent surface of the knife, and cooperating means for yieldingly maintaining the grinding member in the position determined by the gaging mechanism.

3. A skiving machine comprising a tubular skivin g knife, means for forming a bevel cutting face upon the outer surface of the knife, a grinding member positioned in operative relation to the inner surface of the knife, a gage member for limiting the movement of the grinding member toward the surface of the knife, and means for yieldingly maintaining the grinding member in the position determined by the gage member.

l. A skiving machine comprising a tubular skiving knife, an adjustable head, a grinding member supported by the head and projecting within the knife, an adjustable gaging screw for limiting the movement of the head in one direction, and a spring for normally maintaining the head in contact with the gaging screw to locate the grinding member in the position determined by the gaging screw.

5. A skiving machine comprising a substantially cylindrical skiving knife, a grinding disk, means for supporting the grinding disk with its axis parallel to the axis of the knife, means for rotating the disk, and means for moving the disk in a rectilinear path.

6. A skiving machine comprising a tubular skiving knife, :1 head located above the knife, a bracket carried by the head, a grinding disk supported by the bracket and projecting within the knife, and mechanism for adjusting the grinding disk axially in the bracket.

7. A skiving machine comprising a tubular skiving knife, a knife shaft, a grinding disk, means for supporting the disk in operative relation to the surface of the knife, a shaft for rotating the grinding disk connected to the knife shaft and supported concentrically therewith, and connections between the grinding disk and drive shaft.

8. A skiving machine comprising a knife shaft, a tubular skiving knife supported upon one end of the knife shaft, a grinding disk, a shaft supporting the grinding disk within the knifesubstantially parallel to the M operative relation to one surface of the knife, means for rotating the grinding disk, and a sleeve bearing for the grinding disk threadedly engaging With the bracket to permit a bodily movement of the grinding disk in a rectilinear path.

FRANK V. CHRISTY.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner oflatents.

Washington, D. G. 

